1. Field of the Invention
The present invention relates to a cylinder apparatus in which a piston having a piston rod connected thereto is slidably inserted into a cylinder, such as a hydraulic shock absorber, a gas spring, and so on.
2. Description of Related Art
As an example of a hydraulic shock absorber to be mounted in a suspension system of a vehicle such as an automobile, there has been the type disclosed in JP-A-6-101734, in which a rebound spring (a helical compression spring) is wound around a piston rod connected to a piston which is slidably inserted into a cylinder. In this hydraulic shock absorber, when the piston rod has been extended up to a position near its maximum extendable position, the rebound spring is compressed and exerts a spring force against further extension of the piston rod so that it is difficult for the piston rod to arrive at the end of its stroke, and thus the shock at end of the stroke is moderated.
However, the conventional hydraulic shock absorber provided with the rebound spring as described above has had the following problem. When the piston rod has been extended and has arrived at the end of its stroke, the rebound spring will be compressed into the maximum compressed state, and adjacent linear portions of the rebound spring may touch one another. As a result, strange noises may arise, and the rebound spring may be damaged.
The present invention has been made in view of the above described problem, and an object of the invention is to provide a cylinder apparatus in which mutual contact between linear portions of a rebound spring can be prevented.